THE LARVAL AND PUPAL STAGES OF THE BIBIONIDAE 



231 



In addition to the three species described above, larvae of Bibio johannis,. L. 

 (lig. 16), have been examined, and also larvae believed to be those of B. pomonae, F. 

 (fig. 17), but the latter were not definitely identified in the adult state. As will be 

 seen from the illustrations, these two species are quite distinct from the other species 

 figured. 



Fig. 17. Portion of cuticle of larva of Bihio pomonae from 



dorsal surface of fourth segment : a, lateral view ; 



b, vertical view ; the arrows directed anteriorly ; x 330. 



The alimentary canal also varies in some of the species examined, that of 

 B. marci and B. lacteipennis being without the posterior caecum which is present in 

 the canal of B. johannis. This posterior caecum is also absent, according to 

 Keilin (4), from the alimentary canal of B. hortulanus, L. The labium also shows 

 slight variations in different species. 



Parasites of Bibionid Larvae. 



Very few parasites of the Bibionid ae are known. In adcUtion to the mite 

 and nematode recorded by Lyonet, Keilin (4) mentions the Gregarine Schneideria 

 mucronata, Leger, occurring in the mid-gut and anterior caeca of Bibionid larvae, 

 and also a bacterial disease. He further mentions a Microsporidian, probably a 

 Glitgea, which invades the epithelial cells of the mid-gut and caeca of Scatopsid 

 larvae. 



Sorauer (7) gives Agyrtes bicolor as a parasite of the larvae of Scatopse. 



A Gregarine, probably the Schneideria mentioned by Keilin, was found in the 

 posterior caecum of a Dilophus febrilis larva, and in the same larva two cysts' full 

 of spores were found free in the body. Another parasite, probably the Glugea 

 mentioned above, was found infesting the epithelium of the ahmentary canal in a 

 Bibio johannis larva. 



In addition to these a Dipterous parasite was met with in connection with 

 Bibio marci larvae. This was the Phorid Hypocera incrassata, Mg. The fully grown 

 larvae emerged from the B. marci larvae when the latter were about to pupate, 

 and almost immediately entered the pupal state. Only a single parasite was observed 

 in each larva attacked. 



Additions to Literature since 1917. 



In 1917 an account of the larva and pupa of Bibio johannis was published, in 

 which the hterature up to that date was referred to. The following publications 

 have appeared since that date. 



